In vitro activity of antifungal drugs against Cladophialophora species associated with human chromoblastomycosis

The antifungal activity of six drugs was evaluated against 41 clinical and environmental isolates of Cladophialophora carrionii and its sister species C. yegresii. Drugs tested, including their ranges, were: 16-0.016 µg/ml for amphotericin B (AMB), itraconazole (ITZ) and voriconazole (VCZ), 8-0.008 µg/ml for terbinafine (TBF), and 64-0.063 µg/ml for flucytosin (5-FC) and fluconazole (FCZ). Strains were tested according to the CLSI guidelines (M38A). The MIC Gmeans for clinical strains in µg/ml were; 0.02 for TBF and ITZ, 0.07 µg/ml for VCZ, 0.49 for 5FC, 6.14 for FCZ and 9.42 for AMB. The MFC Gmeans in µg/ml were; 0.04 for TBF, 0.13 for ITZ, 0.72 for VCZ, 18.83 for 5FC, 36.16 for FCZ and 31.35 for AMB. The most active drugs against the fungi were TBF, ITZ, VCZ and 5FC. However, for all drugs more than two dilution steps were noted between the MIC and the MFC, indicating fungistatic activity. Despite in vitro susceptibility of C. carrionii to antifungal agents, the efficacy of therapy was shown to be not optimal.